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Aug. 25, 2011 -- Separating puppies from their litters too early may make them more likely to develop behavioral problems as adults, a new study shows.

That's important, the Italian researchers say, because dogs that behave badly as adults may be abandoned by their owners.

A team led by Ludovica Pierantoni, DVM, of Animal Behavior Naples interviewed the owners of 140 adult dogs in Naples, Italy. Half of the dogs had been removed from their litters and were adopted when they were 30-40 days old. The other dogs had been taken from their moms and sibling pups at 60 days.

Dog Owners Queried About Pets’ Behavior

When the dogs were at least 18 months old, their owners reported any troublesome, annoying, worrisome, or otherwise problematic behaviors in their dogs. The list included excessive barking, aggressiveness, play biting, destructiveness, possessiveness about food and toys, and eating inedible objects.

With few exceptions, such as eating inedible objects or being aggressive toward their owner, problem behaviors were more likely to occur in dogs that had been separated from their litters before they were 60 days old, especially if they came from pet shops.

This was true regardless of the dogs' breed, neuter status, or size.

Pups Are Sensitive

The early phase of a dog's life is a "sensitive period," the researchers write. The experiences dogs have during that time help shape their temperament.

“Early separation from the dam [mother] and littermates, especially when combined with housing in a pet shop, might affect the capacity of a puppy to adapt to new environmental conditions and social relationships later in life,” the researchers write.

They suggest behavioral intervention to help stop problem behaviors. That, in turn, could help curb the number of dogs that are given up or abandoned by their owners.